1. Field of the Invention
The present invention relates to a whip antenna and a method for manufacturing the same.
2. Prior Art
Various types of antennas are used as automobile radio receivers. Among them, single-length whip antennas can be manufactured at low cost while still maintaining the necessary reception standard.
The receiving section of the single-length whip antenna is made of a single conductive rod which is matched to a quarter wavelength of the FM band. Once such an antenna is mounted on a vehicle, it is exposed outside of the vehicle. Accordingly, a material having high tensile strength and high recovery properties (e.g., high tensile strength stainless steel) is used so that the whip antenna can withstand loads applied by obstacles during the operation of the vehicle and when the vehicle is driven into a car wash, garage, etc.
Some antennas of this type are tapered to increase the recovery property, that is the antenna's ability to return to its original state after being bent by loads.
One example of such a taper-shaped antenna is described in the Japanese Utility Model Application Publication (Kokoku) No. 51-11305. This antenna utilizes a multiple number of stepped elements formed by stamp forging, and a rounded top element is attached to the tip of the antenna. In other words, the top element is manufactured separately from the antenna and then attached to the tip end of the antenna by press fitting, etc. Thus, extra processing steps are required in the manufacture of tapered antennas, and a high precision work is required to form the tip end of the antenna so that the top element attaches easily and securely.